They say it's between a 5% & 12% chance of death for someone Trump's age & given he is not the healthiest specimen, I expect he would be around the 10% risk range.
Boris looks like a bloke that drinks too much, eats poorly, smoked a lot at some point and had high blood pressure. I think he got to the coin toss stage. I won't be surprised if Trump does too. But he does play golf, albeit in a cart, so does get some excercise.